Is the fan running fast and making very loud. If so, you make to reorient a wire. It is either a heat senser or fan sensor wire.I don't remember the exact name. It has white dot on the conector. You need to turn it 180* from how it was before installed your new hard drive. Infix it has a very good guide that explains it.
You can get a disk image download from the mac site. Here is link that may help. Click or tap on the blue link. I have also included the phone number for Apple. They were very helpful and free. They helped me with a 7 year old computer. I had the exact same situation. Good luck. 1-800-442-4000 https://support.apple.com/kb/DL1884?view...
Here is a video that will help. The base of the tank is probably caulked. Use a putty knife to cut the caulking and separate it from the floor. I also would suggest using rubber gloves. Tap or click on the blue link. I hope this helps. Good luck! https://m.youtube.com/watch?v=wUxFAJ5lEm...
Here is a link that explains how to turn off airplane mode. Tap or click on the blue link. I hope this helps. Good luck! http://www.htc.com/us/support/htc-one-m8/howto/465119.html
Here is a link to a site that explains how to get your computer working. Tap or click on the blue link. I hope this helps. Good luck! https://neosmart.net/wiki/compaq-recovery-disk/
I am not sure if the antenna can be replaced. However, here is a link to a parts house that I think will be able to answer your question. Tap on or click on the blue link. I hope this helps.Good luck! http://www.craigcommunications.com/inter...-900-0400-int4000-digital-cordless-phone.asp
Here is link for the part you need. It is on Amazon and many other site. Just make sure it is the right one for your unit. Tap or click on the blue link. I hope this helps. Good luck! http://www.ebay.com/bhp/ps2-slim-power-cord
Here is a much easier solution. It is called a chilling mat or cooling stand. It has fans in it. You just plug it into a USB port on your computer. Problem solved. Here is a link I found. Tap or click on the blue link. You can buy these many different places on line and in local stores. This should help. Good luck! http://store.hp.com/us/en/pdp/targus-chill-mat-cooling-stand
Here is a link that may help. It is for the part your looking for. Tap on or click on the blue link. I hope this helps. Good luck? http://www.allpartsmac.com/NEW-IMac-27-A